Method of making surgical casts



April 1935- R. G. ASHBY 1,996,228

METHOD OF MAKING SURGICAL CASTS Filed June 30, 1934 Patented Apr. 2,1935 .Mizrnon or MAKING SURGICAL CASTS I, Richard Ashby, Clayton, Mo.Application June 30, 1934, Serial No. 733,159

2 Claims.

This invention relates to a method of making bandages, and with regardto certain more specific features, to a method for making bandages orthe like, for use in making surgical casts of plaster of Paris or likehydraulic cements.

Among the several objects of the invention may be noted the pro-visionof a plaster-of-Parisimpregnated bandage for use inm'aking plaster ofParis casts and the like which shall carry a more uniform charge ofthoroughly wet plaster of Paris; the provision of a bandage of' theclass described which, for a given area of fabric, retains for ultimateuse in'the cast a greater percentage of the plaster oflParis originallyapplied; and the provision of a bandage of this class which may, withless difficulty than heretofore, be more quickly and cheaply made. Otherobjects will be in part obvious and in part pointed out hereinafter. I

The invention accordingly comprises the elements and combinations ofelements, features of construction, and arrangements'of parts which willbe exemplified infthe structures hereinafter described, and the scope ofthe applicationof which will be indicated in the following claims.

In the accompanying'drawing, in which is 11- lustrated one ofvariouspossible embodiments of the invention,

Fig. 1 is a diagrammatic layout of the invention, shown partly insection and partly in elevation;

Fig. 2 is a longitudinal section taken through a strip of bandage woundon a support, the latter being shown in elevation;

Fig. 3 is a cross section taken on line 3-3 of Fig. 2; and,

Fig. 4 is a plan view of a fragmentary portionof fabric showing animproved integumentary edge thereon.

Similar reference characters indicate corresponding parts throughout theseveral views of the drawing.

Heretofore plaster of Paris casts have been made substantially asfollows:

A strip of crinoline or like fabric has been either cut or torn into astrip of suitable width and length. This has then been passed over aflat apron and then wound on to a winding staff or drum. While passingover the apron, the fabric has had powdered plaster of Paris appliedthereto and rubbed into the fabric surface so as to force the powderedplaster of Paris into the reticulations between threads. Thesereticulations retained the plaster of Paris in position between layersof fabric as the same was rolled up on the staff or drum. After thelength had been com- H pletely wound up, a fastener, such as a rubberband was applied around the same and a protecting paper or like wrapperplaced thereabout.

To prepare the bandage for use, it was im- 5 mersed in a vessel ofwater. The water found its way through the reticulations and to theplaster of Paris under the effect of gravity. After a suitable time, thewet bandage was removed and v applied by wrapping on the limb or thatwhich 10 was to be placed in the cast. I

The disadvantages of this method of preparing a bandage for a castwerethat, in the first place,

an even layer of powdered plaster of Paris in v the original strip wasnot a'ssuredQbecause of 15;

the irregularities in,.the cloth surface and reticulations. Secondly,the powdered plaster of Paris after application to the bandage absorbedwater of hydration hygroscopically, thus effecting a partial pre-settingof more or less of the plaster 20 of Paris. .Thirdly, the. water, afterimmersion" did not find its way into the cloth in a consistent manner,thus leaving more or less dry 'spots' of plaster of Paris and presentinga heterogeneous layer of plaster of Paris in the ultimate cast. 25Fourthly, a large percentage of the plaster of Paris was lost from thebandage in the immersion, because gravity tends to causethis to settleout, as well as to force the water into the fabric.

Coming now to the present invention, and referring more particularly toFig. I, there is shown at numeral I a vessel adapted to withstand asuper-atmospheric pressure of a substantial amount, for example, severalatmospheres or 35 more. This vessel is provided with a cap 3 having asealing gasket 5 between it and the vessel I and adapted to be held downby means of a thumb screw 1 threaded through a bail 9. The cap 3 is thusremovable.

An inlet nipple is adapted to have a quick detachable coupler I3 appliedthereto, the latter being on the end of a flexible hose I5 leading froma pressure tank II. The tank I! is maintained under pressure by anyknown compressor system I9.

A relief cock 2| is also provided in the cover 3, as well as a suitablepressure gauge 23. I

The vessel I is filled with a mixture 25 of water and plaster of Parisof the consistency re- 5 quired in bandages of this class. It may bethick or thin, depending upon the particular requirements.

The bandage fabric is preferably composed-of crinoline 21 illustrated inFig. 4. This is rather coarse material, and when out or torn presents aravelled edge which interferes with subsequent proper manipulation. Inorder to prevent the ravelling from being deleterious, I apply awaterproof but subsequently flexible integumentary material to theedges, such as collodion 28. This quickly dries and does not interferewith the subsequent bandaging operation. This feature of theintegumentary edge I consider also to be new. It is to be understoodthat the collodion is a class example of an integument for preventingunravelling which has the qualifications desired.

The fabric strip is then wound upon a support 29 which has spacedfingers 3| and a holding ring 33. A retaining band 35, such as anordinary rubber band, is provided about, the bandage after it has beenwound.

The wound and supported bandage is then immersed in the liquid 25.Immediately the cover 3 is applied to the vessel l and clamped down, thecock 2! being shut. Next, the quickdetachable coupler I3 is applied tothe nipple l I. It is to be understood that this connection carries anautomatic valve which opens upon application of the coupler IS, the hosel5 being normally under pressure. Quick-detachable couplers andautomatically opening valves of this class are well known.

The above operation,. it will be seen, immediately placessuper-atmospheric pressure upon the liquid 25 which is instantaneouslyforced into all of the reticulations of the bandage. The hydrostaticpressure is efiected on the outside of the roll, as well as on theinside within the fingers 3| and thus quickly reaches all regions of thefabric, carrying into the same the suspended charge of plaster of Paris.

The purpose of the spaced fingers 3| is not only to provide means forwrapping the roll but also to prevent incipient collapse thereof underthe initial application of pressure. It will be understood thatincipient collapse is prevented, thereafter collapse does not progress,because of the core of liquid between the fingers 3| under hydrostaticpressure equal to that of the liquid outside of'the roll.

The advantage of the super-atmospheric pressure is the quick andthorough action in impregnating the cloth with the plaster of Parissolution. Under atmospheric pressure this does not occur assatisfactorily. Also, there is no loss of material from the bandage, aswhen water works into a dry charged bandage under the old procedure.

The immersion under pressure is short. A disconnection of the coupler I3is quickly made and the blow-oil cock 2| opened. This relieves thepressure and the tank may be opened to reinove the bandage forunwrapping and applica- It will be understood that the degree ofpressure in-the tank may be varied, but I have found that the pressureof the order of eighty pounds per square inch is satisfactory.

It is to be understood that as many rolls may be placed in a givencontainer l as the operator may desire, or a battery, of containers maybe employed. In fact, many refinements of design may be likewiseaccomplished without departing from the scope of the invention.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As many changes could be made in carrying out the above constructionswithout departing from the scope of the invention, it is intended thatall matter contained in the above description or shown in theaccompanying drawing shall be interpreted as illustrative and not in alimiting sense.

I claim:

1. The method of making a surgical cast comprising rolling a strip offabric, immersing said rolled fabric in a mixture of water and cement,applying super-atmosphere pressure to said mixture while said fabric isimmersed, removing the pressure, removing the fabric from the mixture,and immediately unrolling the same and applying it.

2. The method of making a surgical cast comprising rolling a strip offabric, immersing said rolled fabric in a mixture of water and plasterof Paris, applying super-atmospheric pressure to said mixture while saidfabric is immersed, removing the pressure, 'removing the fabric from themixture, and immediately unrolling the same and applying it, saidpressure being of the order of several atmospheres or more.

RICHARD G. ASHBY.

